Injector for radioactive gas



United States Patent O 3,493,757 INJECTOR FR RADIOACTIVE GAS James J. Glenn, Jr., Long Beach, Calif., assignor to Triangle Service, Inc., Long Beach, Calif., a corporation of California Filed May 2, 1966, Ser. No. 546,688 Int. Cl. G21h 5/00; G01n 23/12; H01j 37/00 U.S. Cl. 250-106 4 Claims ABSTRACT OF THE DISCLOSURE In order to calculate the amount of gas which is flowing into an oil well from the surrounding strata, a gas is injected through an appropriate tool into the casing of the oil well and that tracer gas is subsequently detected at a remote point from its injection; thus determining the velocity of the incoming gas and, consequently, the amount of gas which is owing into the bored hole of the oil well.

This invention relates to a gas tracer injector to determine the velocity of incoming gas into the casing of an oil or gas well, and thus the amount of incoming gas can be calculated.

The operation of my injector in a well can also determine the approximate point of entrance of gas or other products into the bore of the well.

An object of my invention is to provide a gas tracer injector for oil or gas Wells which will eectively and accurately introduce a radioactive isotope into the bore of the Well in a gradual manner, so that a gamma ray counter in the injector or adjacent thereto can determine the increase or decrease of the isotope in the area around the tool.

Another object of my invention is to provide a gas tracer injector in which a radioactive isotope is injected or pumped into the bore of the well through which the tool passes at governed intervals, thus enabling the tool to remain in the well for a substantial period of time, and to determine the presence or ow of gas in the well by reason of various injections of the isotope into the bore of the well, which injections may be continuous or spaced as determined by the operator. l

Another object of my invention is to provide a novel gas tracer injector in which different types of radioactive isotope may be used, for example, an isotope which is soluable or miscible therewith so that it will be possible to locate and follow the gas movement as it enters a well, and subsequently thereto.

Another object of my invention is to provide a novel gas tracer injector in which the radioactive isotope is pumped or expelled from the tool at regular or intermittent periods, either while the tool is moving or while it is stationary.

Other objects, advantages and features of invention may appear from the accompanying drawing, the subjoined detailed description and the appended claims.

In the drawing:

FIGURE 1 is a side elevation of my gas tracer injector.

FIGURE 2 is a fragmentary vertical sectional view of the lower portion of my gas tracer injector.

FIGURE 3 is a fragmentary vertical sectional view of the upper part of my gas tracer injector.

FIGURE 4 is a sectional view taken on line 4-4 of FIGURE 3.

Referring more particularly to the drawing, the numeral 1 indicates the outer cylindrical or tubular housing, and which is provided with a suitable cable socket 2 at its upper end, which is usual and well known in the art. A cable 3 is attached to the socket 2 and extends to the surface where electrical leads extending through the cable 3,493,757 Patented Feb. 3, 1970 ICC can be controlled by the operator. The cable 3 `also acts as a means of supporting or moving the tool in the bore of the well. The housing 1 includes a sleeve 4 at its upper end or adjacent to the upper end, and this sleeve has a gamma counter S mounted therein, which is usual and well known in the art. The gamma counter has a self-contained power unit (not shown), but which is also positioned in the tool or within the sleeve 4. Suitable ports or slots 6 in the sleeve 4 permit gas to move from the bore of the well into the space around the gamma counter so that the gamma counter may function.

The electric line or wire which extends downwardly through the cable 3 is indicated at 7, and this lead extends to the motor 8 to supply power to the motor. The motor 8 is ixedly positioned within the housing 1 and is provided with the drive shaft 9 and this shaft, in turn, is connected to a coupling 10 which extends through a bearing 11. The bearing 11 is ixedly mounted within the housing 1 in any suitable manner, so that it will adequately support the shaft 9. A threaded shaft 12 extends downwardly from the coupling 10 and this shaft is threaded into a nut 13 which is mounted for vertical movement in the housing 1, but is prevented from rotating by engagement with the vertical ribs 14. An operating tube extends downwardly from the nut 13 and may be an integral part of this nut. It will move vertically within the housing 1 with the nut 13 as the threaded shaft 12 is rotated, as will be A evident. In FIGURES 2 and 3 the nut 13 and the tube 15 are shown in their lowermost position. Rotation of the threaded shaft 12 will cause both the nut 13 and the tube 15 to move upwardly.

At its lower end the tube 15 has an extension tube 16 secured thereto, and this extension tube passes through the coupling 17 and thence into `a chamber 18 below the coupling 17. A piston 19 is attached to the extension 16 and reciprocates within the chamber or cylinder 18 as the tube 15 moves upwardly or downwardly. A packing ring 20 on the piston 19 will prevent leakage around the piston to insure that the radioisotope will be ejected from the cylinder 18, as will be subsequently described.

Radioactive isotopes in gaseous form, such as methyliodide, are retained and transported in glass or plastic vials or tubes. This is a safe and effective Wap of handling the isotope, and in my invention the gaseous isotope is never removed from the vial in which it is transported. This glass vial, indicated at 21, is positioned in the cylinder 18 before the tool is run into the well. The vial is positioned lbetween the piston 19 and its lower end, and the coupling 17 at its upper end. Thus when the piston 19 is caused to move upwardly by operation of the motor 8 the glass or plastic vial 21 will be crushed, thus releasing the gaseous isotope and permitting the isotope to mix with whatever gas might be present in the cylinder 18. A relatively small further upward movement of the piston 19 will compress the gas in the cylinder 18 and causing a small amount of gas to be discharged upwardly through the space 22 in the coupling 17 and surrounding the extension 16. A metering jet 23 extends from the chamber 22 to the outside of the tool or into the bore of the well. Thus a small amount of gaseous isotope would be ejected through the metering jet 23 where it mixes with the gas or other fluid surrounding the tool and Will move upwardly around that tool, to be subsequently identified by the gamma instrument 5. After each short movement of the piston 19 the motor 8 will be deenergized until the gamma instrument 5 has ybeen activated, and thus completing this particular step in the tracing of gas within the well. If subsequent tests are required, short periods of activity of the motor 8, as controlled from the surface, will eject additional quantities of the isotope into the bore of the well, thus permitting a series of tests until the piston 19' has moved the entire 9 length of the cylinder 18. By calculating the interval of time for the radioactive gas to move from the metering jet 23 to the gamma counter 5, it is possible to mathematically determine the velocity of the gas as it moves upwardly in the bore of the well.

If desired, a plurality of ports 24 may be provided in the wall of the housing 1, and these ports extend to a point below the piston 19 to equalize pressures below the piston, and so that the piston can easily move when the motor 8 is energized. The subassembly 25, which screws into the lower end of the housing 1, may contain other testing equipment which, however, is not a part of my present invention.

Having described my invention, I claim:

1. A gas tracer injector comprising an elongated tubular housing, said housing having a cylindrical space therein, a piston slidably mounted in said cylinder, motor drive means within said housing and operatively connected to said piston to move said piston longitudinally within the cylinder, means remotely spaced from the motor drive to control the operation of the motor, a metering jet in said housing extending from said cylinder at one end to the outside of the housing at the other end, and a breakable means within the cylinder containing a gaseous radioactive isotope, said means being breakable by the `piston on longitudinal movement of the piston in the cylinder to thus release the radioactive isotope into the cylinder.

2. A gaseous tracer injector as recited in claim 1, ,and wherein the breakable means containing the radioactive isotope is a vial formed of glass, said vial bearing against one end of piston.

3. A gas tracer injector as recited in claim 1, `and wherein the power means within the housing comprises a motor within the housing, a threaded shaft driven by the motor, a nut threaded on said shaft, means in the housing engaging the nut to prevent rotation thereof to thus cause reciprocation of the nut on rotation of the shaft, and means extending from the nut to the piston to reciprocate said piston within the cylinder.

4. A gas tracer injector as recited in claim 1, and wherein the power means within the housing comprises a motor within the housing, a threaded shaft driven 'by the motor, a nut threaded on said shaft, means in the housing engaging the nut to prevent rotation thereof to thus cause reciprocation of the nut on rotation of the shaft, and means extending from the nut to the piston to reciprocate said piston within the cylinder, said breakable means consisting of a glass vial shattered by the, piston on movement of the piston by the motor, said vial bearing against one end of the piston.

11/1948 Pety. 6/1961 Bohn. 11/1961 Egan et al.

ARCHIE R. BORCHELT, Primary Examiner 

